An information display apparatus in which a text content and a dictionary database are incorporated is equipped with a marker function in order to improve learning effects. As used herein, the term “marker function” refers to a function for storing, when an operation for registering a character string in a text as a marker display character string is received from a user, position information of the character string, and for displaying the character string with a marker to accentuate the character string when the same text is displayed later (see JP-A-2002-7420 and JP-A-2004-213299, for instance).
Further, for an information display apparatus equipped with such a marker function, a technique for displaying a marker display character string in a hidden manner has recently been proposed (see JP-A-2006-293186, for instance). With this technique, a character string portion displayed in a hidden manner can be used for rote learning, thus enabling further improvement in learning effects.
Actually, when a large number of marker display character strings exist in a text, display thereof is complicated, and it is difficult to know the importance of each marker display character string. This may reduce learning effects. Therefore, when a plurality of marker display character strings exist in a text, registration as the marker display character string is preferably cancelled for the character string whose importance reduced.
However, in the technique, when a plurality of marker display character strings exist in a text, a user is forced to determine which marker display character string should be subjected to registration cancellation by himself or herself, thus requiring much time and effort.